#bgdiv {
position:fixed;
top:-50%;
left:-50%;
width:200%;
height:200%;
z-index: -100;
}
#bgdiv img {
position:absolute;
top:0;
left:0;
right:0;
bottom:0;
margin:auto;
min-width:50%;
min-height:50%;
}
.picker {
float: right;
}